B1 Flashcards
(106 cards)
0
Q
Name the two stages of heart pumping.
A
- Heart relaxes to fill with blood
2. Heart contracts to squeeze blood out in arteries
1
Q
What is the job of the circulatory system?
A
- To carry oxygen and glucose in blood to all bodily cells
* So that energy can be released through aerobic respiration
2
Q
Why is blood under such high pressure when it’s pumped out of the heart?
A
- To ensure that the blood reaches all parts of the body supplying cells with glucose and oxygen for respiration
- Blood in arteries is always under high pressure
- This surge of blood is the heart beat or pulse
3
Q
What is blood pressure and how is it measured?
A
- Blood pressure is as measure of the force of blood per unit area as it flows through the arteries
- It’s measured in mm Hg (millimetres of mercury)
4
Q
What is systolic blood pressure?
A
• The first number is the pressure in your arteries when your heart contracts i.e. the highest number
5
Q
What is diastolic blood pressure?
A
- The second number
* The pressure in your arteries when your heart relaxes
6
Q
What is the average, healthy reading for systolic and diastolic blood pressure?
A
120 over 80 mm Hg
But this is affected by lifestyle factors and age
7
Q
How can you reduce high blood pressure?
A
- By doing regular aerobic exercise to strengthen your heart
* Also a healthy diet can also help by maintaining a steady weight
8
Q
What factors can lead to high blood pressure and how do they do it?
A
• Excess weight - the circulatory system has to work harder to pump blood around the body of a person is overweight
• High stress levels
• Excess alcohol
• A diet which is high in sat fat, sugar and or salt. Too much salt can raise blood pressure, whilst too much sat fat can lead to build-up of cholesterol in the arteries forming plaque. The amount of cholesterol in the arteries can be linked to the amount of saturated fat eaten. This plaque bulges into the lumen, restricting or blocking blood flow through the arteries, increasing the risk of heart attack
• Smoking - carbon monoxide produced reduces the oxygen-carrying capacity of the blood so the heart rate and pressure increases in order to compensate. Plus, nicotine increase the heart rate.
HT - carbon monoxide takes the place of oxygen in the haemoglobin so the oxygen-carrying capacity of the blood is greatly reduced
9
Q
What are the long term risks of high blood pressure?
A
- Blood vessels can weaken and eventually burst
- If a blood vessel bursts in the brain it may lead to brain damage/stroke
- in the kidneys it could cause kidney damage
10
Q
What effects does low blood pressure have on the body?
A
- Blood doesn’t circulate efficiently
- Some part of the body are deprived of glucose and oxygen
- This can lead to dizziness, fainting, and cold hands and feet
- Also pressure may drop in the kidneys leading to kidney failure
11
Q
What factors increase the risk of heart disease?
A
- High blood pressure
- Smoking - carbon monoxide combines with red blood cells, preventing them from carrying as much oxygen
- Too much salt
- High-fat diets - block arteries + cause heart attacks. Heart attacks are more likely with narrowed coronary arteries and thrombosis
12
Q
Define: healthy
A
• Being free from infection - no coughs, colds or diseases
13
Q
Define: fit
A
- How much physical activity you are capable of doing and how quickly your body recovers afterwards
14
Q
Define: cardiovascular efficiency
A
• How well your heart copes with aerobic exercise and how quickly it recovers afterwards - is often used as a measure of general fitness
15
Q
What three things should a balanced diet contain?
A
- Carbohydrates
- Fats
- Protein
16
Q
What are carbohydrates, fats and proteins made up of?
A
- Carbohydrates are made from simple sugars such as glucose
- Fats are made up of fatty acids and glycerol
- Proteins are made up of amino acids
17
Q
How are carbohydrates, fats and protein stored?
A
- Carbohydrates are stored in the liver as glycogen or can be converted to fats
- Fats are stored under akin and around organs as adipose tissue
- Proteins are not stored
18
Q
Although they don’t provide energy what other substances do you need in your diet to keep your body healthy?
A
- Minerals - e.g. iron to make haemoglobin in red blood cells
- Vitamins - e.g. Vitamin C to prevent scurvy
- Fibre - to prevent constipation and to maintain healthy bowels
- Water - to prevent dehydration and to help remove waste
19
Q
Why might someone alter their diet?
A
- Beliefs - about animal welfare (vegetarians/vegans)
- Religious beliefs - for example Muslim and Jewish faiths prohibit eating pig
- Medical issues - such as allergies or intolerances
- Age - more/less calories and protein
- Sex - males need more calories dope to being larger and having more muscle
- Activity levels - someone with a more active profession would need more calories
- Personal choice
20
Q
How can you maintain a healthy body mass?
What happens if you don’t?
A
- You must balance the amino if energy you consume the amount of energy you use up through daily activity
- If you consume more food than you need you will become overweight/obese
- Obesity is a major problem in the developed world. It can lead to arthritis (swollen and painful joints), heart disease, type II diabetes and breast cancer
21
Q
Protein molecules are made from long chains of ….?
A
• Amino acids
22
Q
Where are essential/non essential amino acids found?
A
- Essential - taken in by eating food (the body can’t make them)
- Non-essential - can be made in the body
23
Q
Why is it so important for teenagers to have a high-protein diet?
A
• Protein supplies enable you to grow!
24
Why might people have protein deficiencies?
Where might people have these especially?
Name a disease that occurs because of protein deficiency.
* People that don't have access to protein or enough food to live healthily
* Developing countries (LEDC's)
* Kwashiorkor
25
Formula for calculating your estimated average daily requirement for protein (EAR)
What can make an EAR vary?
EAR = 0.6 x body mass in kg
• Whether someone is pregnant or lactating and their age
26
When is protein used as an energy source?
• When carbohydrates or fats aren't available
27
What factors may lead to poor diet?
* Poor self-image
* Low self-esteem
* Desire for perfection
28
Name two eating disorders and explain why they are so damaging to the body?
1. Anorexia nervosa
2. Bulimia nervose
• The body does not get the balance of energy and nutrients to function properly.
• The reproduction system may be affected as well as bone damage
29
Define: non-infectious disease
* A disease which cannot be caught from another person
* Not caught/passes on
* No pathogens involved
30
What can cause a non-infectious disease?
* Poor diet - e.g. Lack of vitamin C causes scurvy
* Organ malfunction - e.g. the pancreas stops producing insulin causing diabetes
* Generic inheritance - e.g. People inherit genes for particular diseases like red-green colour blindness
* Cells mutate - causing cancer
31
What is cancer?
• Cancer is a non-infectious disease where cells grow out of control and form tumours
32
How can you reduce the likelihood of developing cancer?
* Don't smoke - chemicals in cigarettes cause lung cancer + other cancers like throat cancer
* Don't drink excess alcohol - alcohol is linked to cancer of the liver, gut and mouth
* Avoid getting sunburn - skin cells damaged by the sun can mutate and become cancerous
* Eat a healthy diet - a high-fibre diet can reduce the risk of bowel cancer
33
Describe the division of cancerous cells.
• Cancerous cells divide in an abnormal and uncontrollable way, forming lump cells called tumours
• A tumour that grows in one place is called benign
• If it breaks off and spreads to other areas of the body it becomes malignant
•
34
What affects a person's chances of surviving cancer?
* Type of cancer
* Time of diagnosis
* Age of the person
* Whether it is benign
35
Describe the characteristics of infectious diseases
* Spread from one person to another
| * Caused by pathogens (microorganisms that attack and invade the body)
36
Give examples of infectious diseases and their causes.
* Athlete's foot - fungus
* Flu - virus
* Cholera - bacterium
* Malaria - protozoan
37
Describe the stages of mosquitos (vector) spreading.
1. A mosquito sucks blood from the human (host)
2. If there are malaria parasites in the blood, they mate and move from the mosquito's gut to its salivary gland
3. The mosquito then bites another person and passes the malaria parasites into their bloodstream.
4. The malaria parasites move to the liver, where they mature and reproduce
5. The new generation of malaria parasites migrates to the blood and replicates in red blood cells, bursting them open. This damage leads to characteristic malaria fever and can sometimes result it death
38
How can the risk of the spread of malaria be reduced?
* Sleeping under a mosquito nets
* Using insect repellent
* Killing Mosquitos with pesticide
39
What defences does the body have against pathogens getting in?
* The skin acts as a barrier against microorgansims
* Blood clots in wounds to prevent microorganisms from entering the bloodstream
* The respiratory system is lines with cells that produce a sticky, liquid mucus that forms a mucus membrane to trap microorganisms
* The stomach produces hydrochloric acid which kills microorganisms in the food we eat
40
Name the two ways the two types of white blood cells deal with pathogens.
* By engulfing and digesting pathogens they find in the bloodstream
* By making antibodies to attack pathogens. They recognise the markers on pathogens and produce antibodies which lock onto the markers (antigens) killing the pathogens
41
Describe the stages of a vaccination.
1. A person is injected with a weakened or dead strain of the pathogen, which is incapable of multiplying. It's harmless.
2. Even though the pathogens are harmless, the antigens (markers) trigger the production of specific antibodies by the white blood cells
3. Long after the pathogen has been dealt with, the white blood cells remain in the blood (memory cells are produced). This means more antibodies can be produced very quickly if the pathogen is detected again
42
Benefits of immunisation:
* Protects against diseases which could kill or cause disability e.g. Polio or measles
* If everybody is vaccinated, the disease won't spread and eventually does out (this is what happened to smallpox)
43
Risks of immunisation:
* An individual could have a bad reaction to the vaccine
| * No vaccine is 100% safe! but the benefits outweigh the risks
44
Describe and give an example of passive immunity.
* Passive immunity occurs when antibodies are put into someone's body, rather than them being created by the body. This is used when a quick response is needed or if person has a weak immune system.
* For example, pathogens and toxins in a snake's venom act very faster, so a person's immune system is unable to produce antibodies to destroy the pathogen quickly enough. However, they will have no long term immunity to the pathogens.
45
What diseases are treated with antibiotics?
Those caused by:
• bacteria
• fungi
• NOT VIRUSES
46
What drugs are used to treat disease caused by viruses?
• Antiviral drugs
47
Why is over prescription of antibiotics worrying?
* All the bacteria in a population are killed of except the resistant ones, which then spread
* Antibiotic becomes useless
* MRSA has become resistant to most antibiotics
48
Describe computer models testing.
• This can predict how it will affect cells, based on know information about how the body works and similar drugs responses
49
Describe animal testing
• Show how it will affect a living organism - many people object on the grounds of cruelty
50
Describe human tissue testing
• Human tissue (grown in a laboratory) to see how it affects human cells - some people object to human tissue being grown in this way because they believe it's unnatural and wrong.
51
What does a fair drug trial need to include?
* Drug must be tested on healthy volunteers
* Volunteers must have the disease
* Some must have a placebo
52
What is a blind trial?
* Volunteers don't know whether they've been given drug or placebo
* This eliminates any psychological factors
* Gives a fair comparison
53
What's a double blind trial?
* Doctors and volunteers know which is placebo and drug
* Eliminates all bias from the trial
* Doctor cannot influence patients response
54
What is a receptor?
• Specialised nerve endings that generate nerve impulses
55
What types of receptors do you have a where are they located?
* Light receptors in your eyes
* Sound and balance receptors in your ears
* Taste receptors on your tongue
* Smell receptors in your nose
* Touch, pressure, pain and temperature receptors in your skin
56
What is a neurone?
• Neurones (nerve cells) are specially adapted that carry a nerve impulse. Nerve impulses are electrical messages/signals and are carried along the axon (the long thin part of the cell)
57
What are the three types of neurone?
1. Sensory neurones - carry nerve impulses from the receptors to your brain
2. Relay neurones - make connections between neurones inside your brain and your spinal cord
3. Motor neurones - carry nerve impulses from your brain to your muscles and glands
58
How are neurones adapted to their job?
* An elongated shape (axon) to make connections from one part of the body to another
* An insulating sheath to speed up the nerve impulse
* Dendrites (branched endings) to allow a single neurone to act on many muscle fibres
59
Describe the three steps if an electrical impulse travelling across a synapse.
1. An electrical impulse travels down the neurone until it reaches a synapse (gap between neurones)
2. A transmitter substance diffuses across the synapse
3. The transmitter binds with the receptor molecules on the next neurone, causing an electrical impulse to be stated in that neurone
Neurone A --> Synapse --> Neurone B
Electrical message Chemical Electrical
60
What is a voluntary action?
Voluntary actions are under conscious control of your brain - e.g. Reacting to a stimulus
61
What is a reflex reaction?
• This is an involuntary responses that bypass the brain for a fast, automatic response to protect your body from harm for example:
– pupil reflex automatically controls light entering your eye (preventing damage to the retina)
- knee jerk reaction
- automatically withdrawing your hand from a hot plate to prevent burns
62
What is the pathway that the message takes for a reflex action?
1. Stimulus
2. Receptor
3. Sensory neurone
4. Relay neurone (spinal cord)
5. Motor neurone
6. Effector
7. Response
63
What is the pathway that the message takes for a voluntary action?
1. Stimulus
2. Receptor
3. Sensory neurone
4. Brain
5. Motor neurone
6. Effector
7. Response
64
What does the iris do and how does it do it?
• Controls the amount of light that enters your eye
65
What does the cornea do?
• Refract rays of light entering the eye
66
What is the lens and what does the lens do?
* The lens is a clear, flexible bag of fluid surrounded by circular ciliary muscles that change the shape of the lens - know as accommodation
* Focuses light onto to the retina so the rays converge at a single point to produce a clear image in your retina
67
How do the light receptors in your eyes allow you to see?
• the send nerve pulses along your sensory neurones in the optic nerve to your brain
68
What attaches the lens to the circular ciliary muscles?
• The suspensory ligaments
69
What happens when the eye receives light rays from a nearby object?
1. The ciliary muscles context
2. The suspensory ligaments relax
3. The lens is short and fat the refract light a lot
70
What happens when the eye receives light rays from a distant object?
* The ciliary muscles relax
* The suspensory ligaments contract
* The lens is long and thin to refract little light
71
Name three common eye defects.
1. Long sight
2. Short sight
3. Red-green colour blindness (an inherited condition)
72
What caused red-green colour blindness?
• Specialised cells that pick up red and green light are missing
73
What cause long and short sightedness?
• Caused by the eyeball or lens being the wrong shape so the light rays cannot be of dies accurately on the retina
74
Describe binocular vision.
* Eyes are positioned close together on the front of the head (like binoculars)
* Each eyes has limited view
* Can judge speed and distance accurately
* Found on humans and predators
75
Why is binocular vision better at judging speed and distance than monocular?
• There is a larger overlap of view from each eye. Since the brain has more images to compare from each field of vision it can judge speed and distance far more accurately.
76
Describe monocular vision?
* Eyes are positioned on the sides of the head
* Each eye has a wide field of view - can see behind and in front
* Little overlap in fields of view means judging speed/distance is difficult
* Found on prey
77
Name a the five types of drugs and what they do with an example.
* Stimulants - caffeine, ecstasy, nicotine - increase brain activity, leads to the brain feeling alert
* Depressants - alcohol, solvents, tranquillisers - decrease brain activity which makes you feel tired and slows reactions
* Painkiller/anaesthetics - aspirin, paracetamol, heroin - reduces pain by blocking nerve impulses
* Performance-enhancing drugs - anabolic steroids - increased muscle development, sometimes used by sportspeople
* Hallucinogens - LSD - distort what is seen and heard
78
Describe the drug classification system in the UK.
* Class A - heroin, cocaine - are most dangerous and carry heavy prison sentences and fines for possession
* Class B - amphetamines like speed and barbiturates - have lower penalties
* Class C - tranquillisers and anabolic steroids - are less dangerous and have lower penalties
79
How do depressants and stimulants affect synapses?
* Depressants bind with receptor molecules in the membrane of the next neurone, blocking the transmission of the impulse, slowing everything down
* Stimulants cause more neuro-transmitters to cross the synapse. This speeds up nerve impulses
80
When a drug addict stops taking a drug they can experience...
* Psychological problems such as cravings
| * Physical problems such as sweating, shaking and/or nausea
81
Why is rehabilitation such a hard thing to do?
• Both the body and mind have to adapt to life without drugs
82
List the short term effects of drinking alcohol.
* Lack of balance and muscle control
* Blurred vision and slurred speech
* Poor judgement and drowsiness
* Vasodilation - widening if the blood vessels allowing heat loss
83
List the long term effects of drinking alcohol.
* Liver damage - due to the liver being over worked having to remove toxic alcohol from the body almost constantly
* Brain damage due to dehydration
84
Explain liver damage and cirrhosis.
* The liver contains enzymes which break down alcohol, however during this process toxic by-products are made causing liver damage
* Cirrhosis of the liver is a common disease amongst heavy drinkers
85
What can diseases can smoking cause?
* Cancer of the mouth, throat, oesophagus and lungs
* Heart disease
* Emphysema
* Bronchitis
86
What effects can damage to the cilia, through smoking, cause the body?
* The cilia line the the airways - the trachea, bronchus & bronchioles
* Damage to these then leaves the unable to remove tar and dirt from the lungs leading to the 'smoker's cough' which is the bodies attempt to get tried of mucus
* Excess coughing can damage alveoli and cause emphysema
87
Your body is very good at controlling its constant internal environment this is called...
• Homeostasis
88
What temperature do enzymes in the body work best at?
• 37°
89
What happens if the body gets too hot and why is this dangerous?
* Blood vessels widen and become closer to the ski. So heat can be transferred to the environment
* This is also done by sweating - evaporation of sweat causes heat energy to be removed from skin
* If too much liquid lost through sweat the body can become dehydrated leading heat stroke or death
90
What happens if the body forgets too cold and why is this dangerous?
* Blood vessels constrict, blood flow near to skin is reduced
* Sweating stops
* Muscles start making contractions (shivers), they need energy from respiration but heat is released as by-product
* Hypothermia occurs at 35° or less, resulting in unconsciousness or death
91
What does the brain do to control body temperature.
* Switches between vasodilation and vasoconstriction
| * Negative feedback involves automatic reversal of a change in condition
92
Describe hormones.
* Chemical message released by glands into bloodstream
| * Travel slower than a nervous impulse
93
Name the main glands where hormones are produced.
* Pituitary
* Thyroid
* Pancreas
* Adrenal
* Ovary (females)
* Testes (males)
94
Describe the difference between type I & type II diabetes.
* I caused by pancreas failing to produce insulin causing dip in sugar levels resulting in coma or death sometimes. Treated by insulin injections
* II caused by the body becoming desensitised to insulin, injecting is no use. So it is treated with diet.
95
What do plant hormones control?
* the growth of shoots and roots
| * flowering and ripening of fruit
96
Describe what auxins control and and what they respond to.
• They respond to gravity (geotropism) and light (phototropism)
This causes shoots to grow:
- towards light (positive phototropism)
- against gravity (negative geotropism)
This causes roots to grow:
- away from light (negative phototropism)
- downwards in direction of gravity to absorb water and provide support for the plant (positive geotropism)
97
How does auxin control the plant growing towards the light source?
• Auxin is made in the shoot top
1. The hormones in direct sunlight are destroyed
2. The hormones on the shades side continue to function, causing them to elongate
3. The shoot bends towards the light
98
Name and explain four commercial uses of hormones.
* Rooting powder - encouraging growth of roots from cutting so many plants can be obtained from one plant
* Fruit ripening hormone - causes fruit to ripen, can be accelerated or decelerated if re required for transport or storage
* Control of dormancy - hormones that can be used to speed up or slow down plant growth and bud development
* Selective weed killers - hormones in weed killers disrupt the growth patterns of their target plants without harming other plants. The broader leaved weeds have so larger surface area and therefore get a bigger dose of hormones and due
99
Describe the job of nitrogen-fixing bacteria.
* Converts atmospheric nitrogen into nitrated in the soil.
* Some of these bacteria live in the soil while others live in root nodules with certain plants (legumes) such as peas and beans
100
Describe the job of nitrifying bacteria.
• Converts ammonium compounds into nitrates in the soil
101
Describe the job of denitrifying bacteria.
• Converts nitrates and ammonium compounds into atmospheric nitrogen
102
Define: extremophile
* Organisms that are biochemically adapted to extreme conditions
* They have enzymes that work at different optimum conditions such as bacteria that live in thermal vents
* Some of these organisms live in very cold conditions for example some Antarctic fish posses anti-freeze proteins (AFPs) to prevent ice crystals growing inside tissues
103
Define: specialist
• Specialists are only suited to certain habitats
104
Define: generalist
• Generalists can live in a range of habitats, but can be easily out-competed by other organisms
105
Describe some characteristics of predators.
* Built for bursts of speed
* Camouflaged to avoid being spotted
* Sharp teeth + claws to grab and kill prey
* Eyes at the front of their head (binocular vision) to judge distance and speed accurately
* Have hunting strategy
* Have fewer young as they are more likely to survive to adulthood
